I've got Ofna Ultra/9.5 shocks on my Slash, and it is a nice setup. Much better than the leaky plastic turds the truck comes with.
The only issue would be length, if you're trying to get more downtravel I know on a T4 the front suspension's downtravel is limited where the control arm meets the upright. What you could do is swap it with an RPM front end setup for the GT2, I know with that you can get a couple extra fractions of an inch of downtravel.
The rear control arms should be able to give you all the downtravel you want, but what'll limit you is the inboard camber mount hitting the rear C-brace, and if you overcome that there's the chance the dogbone will skip out of the outdrives.
Also remember that if you put longer shocks on, they might hit full bump before the chassis bottoms out. That'd be a great way to knock the ends off the rear shock tower unless you fabricate some kind of adapter to raise the upper shock mounting positions.